The present invention relates to the placement of three phase ac windings of a coil package into the grooves of an elongated inductor pertaining to and being the stator of a linear motor. This stator is mounted to the underside of a rail plate and carrier so that its grooves face down; the rail plate may pertain to an elongated T-shaped carrier or the like, the rail being the cross bar of the T. It is moreover assumed that the winding that comes as a package is complete at the point of insertion and includes three physically interconnected but electrically insulated flexible cables.
Devices, structure and method of this kind of procedure is disclosed in U.S. Pat. No. 4,557,038 (see also Canadian patent 1,224,912) corresponding to German application 33 23 969 of some of us and others. This known method proposes to bringing a three cable winding package to the installation site by means of vehicle which e.g. runs on that T-shaped carrier. The vehicle may be provided at least with one outriggerlike boom which carries a movable tool arranged to reach down and below the inductor for forcing the windings of the cable package into the grooves and putting them into proper position. The invention improves on this approach.
Linear motors for electrical drives of various kinds are well known in the art. Linear motors include a stator as well as an armature which, contrary to conventional motors, are not arranged on a closed loop but run basically linear straight with of course the possibility of slight curvatures. The electrical energy supplied to this motor is converted into mechanical energy to be immediately and directly available for translatory movement. It is no longer necessary to convert the rotary movement into a linear one whereby certain losses obtain.
Linear motors are usually constructed to have energizing coils arranged in grooves of a stator and the coil or winding system may be arranged to be supplied by a three phase power supply system. The armature element is either constructed as a rail, made of an electrically conductive material such as copper or Al in which case one establishes the equivalence of asynchronous motor. Alternatively, the armature is made of permanent magnetic material which then provides a synchronous motor. Further linear motors are known where a coil is provided in the movable part.
Linear motors are used for example as people movers, for transporting and conveying goods of any kind, for driving movable belts, for baggage transportation, also in mining as feeders for cranes, in drag devices; slides of machine tools are also often operated as and by linear motors; certain mechanical gate structures can be moved by linear motors of this type. Depending on the area of use the motors are relatively short or long, whatever the requirements of movement and displacement.
The coils, as stated, are placed in the stator grooves in a conventional manner which aside from the procedure as per the above reference is a labor intensive procedure. Obviously the longer the stator the more intensive is the labor involved in manufacturing and providing the entire stator assembly including the placement of the windings and loops into the grooves.
The reference mentioned above provides a method and equipment by means of which a prefabricated and premanufactured 3-phase winding package is automatically placed into the grooves of the stator or inductor of a linear motor. The winding package is coiled on a spool which is mounted on a vehicle and as stated a particular tool that extends from the vehicle takes the package off that spool and gradually pushes the package step by step into the grooves of the inductor or stator package.
For this procedure to work it is assumed of course that the stator body is suitably positioned along the path of the vehicle. It is further assumed that the entire range will be covered ultimately by a drive vehicle under utilization of this kind of linear motor. It can readily be seen that this kind of method and the equipment proposed for carrying out the method can place winding packages into the grooves of a stator assembly of any length. Of course the spool holding the package has a limited capacity and has to be replaced by a fresh one every so often. The capacity is often fairly small as compared with the total length to be accommodated so that, relatively speaking, the spool has to be changed rather frequently.
It has to be considered further that one cannot just end with one spool and begin with a new one. Rather respective two packages of windings from the different spools have to be interconnected through suitable sleeves or the like which of course is a job to be undertaken right at the site and constitutes an interruption of the installation procedure as far as placing the loops and windings are concerned. Running the dispensing machine of the type above is comparatively simple on account of the automation. On the other hand making the through connections and placing the sleeves and so forth is a labor intensive procedure requiring highly skilled workmen. There is a certain labor intensity involved which should be replaced through other, more automated procedure.